Non-invasive screening ‘halves Down’s Syndrome births’

Offering non-invasive screening to all pregnant women can half the number of children born with Down’s Syndrome (DS), new research has found.

Researchers from Denmark’s Kennedy Institute found that the number of children born in the country with the condition dropped by 50 per cent after new guidelines suggested that the availability of ultrasounds and blood tests to check for it should be extended.

Until September 2004 the Danish government had recommended that only pregnant women aged over 35 should be offered the combined non-invasive tests, which are carried out between the 11th and 14th weeks of pregnancy.

But Denmark’s national health board subsequently recommended that all women who requested it should be allowed to undergo an ultrasound to measure nuchal translucency in their foetus, along with a maternal blood test to determine whether their baby would be at increased risk of a suffering from a chromosomal abnormality.

After analysing the impact of the new policy, researchers found that in addition to a drop in the number of children born with DS, the number of pregnant women undergoing invasive pre-natal diagnostic procedures dropped from 11 per cent to around six per cent of all pregnancies.

Invasive procedures, such as chorionic villus sampling or amniocentesis, are offered to pregnant women if non-invasive tests indicate that there may be an elevated risk of their baby having DS. Medics can subsequently confirm the condition or rule it out.

Professor Karen Brondum-Nielsen, who is due to report the findings at the annual conference of the European Society of Human Genetics today, said: “We found that making non-invasive screening available to all pregnant women meant that the numbers of invasive procedures decreased by forty per cent between 2004 and 2006.

“Although we have not yet studied the whole of the population, these numbers are significant enough to show that the new guidelines have been accepted by a great majority of Danish parents,” she added.

However the professor concluded that there was a need to analyse the psychological impact of the policy, both in regard to the pre-test counseling available to pregnant women and their attitudes towards screening.

According to the Down’s Syndrome Association one in every 1,000 babies born in the UK has the condition, which is caused by the presence of an extra chromosome in a baby’s cells.

In a report published by the association last year, the charity warned that parents were being given little or no information about DS before agreeing to pre-natal testing for the condition.